The Wings Cup victory was almost ten years ago now. As far as the Hawks, they did win with Handzus there but that's the case of a team that's already won with a core of lot of talent in other areas. There's always going to be an exception or two, but you're going to need HOF talent and top level talent in a lot of other areas if you wanna win without a C line that can battle in today's league.
The flipside in this thinking is saying a team doesn't need a #2D because PITT and WAS won without a real #2 and with fairly mediocre D overall.
My opinion is that you win a Cup if you have a great roster. There are lots of way to spread that greatness around. Maybe it's 2 #1C, a great wing and a #1 D. Maybe it's 2 #1 D, a #1C and 2 Great Wings.
When talking about "recent Cups" you are dealing with a small sample size and correlation that doens't necessarily prove causation. Nobody is going to have 2 Cs like Malkin and Crosby, yet they haven't won every year, and CHI has shown you can win without that model. Poehling may not end up being a #2C, but if he is a #2C (say 50-60 pts and very good D) and the team is strong in other areas it probably won't matter.
It's like having a 1B who only hits 15 home runs. Sure, you'd like your 1B to hit 20 or more, but if you have a C or SS hitting above the avg # for their positions, it probably doesn't matter. The question is, will he be that 50-60 pt guy and will MTL have a good enough rest of the roster.
Both of those remain to be seen.